Everyone was ok using GL5 in manual trans in usa

Status
Not open for further replies.
Joined
Sep 1, 2015
Messages
2,876
Location
Malaysia
... GL5 was good in manual transmissions for the past 20 to 30 years , true ??




..and there is a resurgence of GL4 in the past 3 years ...... attributable to marketing ?
GL4 and GL5 oils in manual transmissions
..at 13.25


So, wondering why the fuss on Bitog ?


Source:GearBoxVideo
 
Last edited:
Your car manufacturer specifies what oil to use.

Over the last 25 years, all of my cars (VW/Audi/Hyundai/Kia) used GL4.

This is not a USA thing.
 
It surprises me if there are actually more GL4 oil choices to day than there was 10 years ago. The percentage of passenger vehicles on the road with a manual transmission is declining every year.
I have used a GL5 MT-1 oil in a transmission once. It was too slippery and didn't allow fast gear changes without crunching the gears. I quickly swapped to a GL-4 oil , Sta-Lube 85W90 from Napa and everything was fine again.
 
No GL-5 gear oil ever got into my manual transmissions. And they all have to gone to the scrap yard working fine. I'll keep on using GL-4 or what the manufacturer recommends.
 
I have counted a number of GL-4 lubes from major refiners that have left the market in the last 10 years. What are the new/“resurgence” ones? On his website, I am thinking it is referring to limited boutique oils like from Brad Penn, etc. Which is a poor substitute for the fact used to be able to go into an auto parts store and get them. They seem to be vastly less available now than a few years ago.
 
My old Toyota Supra allowed for either 4 or 5

I always used Mobil 75w-90 GL-5 because that's what was available at AutoZone back in the 90's



Now I use Amsoil MTG GL-4 for most manuals
 
Originally Posted By: Oro_O
I have counted a number of GL-4 lubes from major refiners that have left the market in the last 10 years. What are the new/“resurgence” ones? On his website, I am thinking it is referring to limited boutique oils like from Brad Penn, etc. Which is a poor substitute for the fact used to be able to go into an auto parts store and get them. They seem to be vastly less available now than a few years ago.



Yea its much harder to find GL-4 now then back when I was a tech, 20+ years ago. And when you are able to find it the price is higher as its a smaller bottler usually. Even amazon stopped carrying the valvoline 75W90 Gl4 I bought before.
 
For the past 20 yrs numerous manual transmissions have been using factory specced ATF, never mind GL4 or GL5 fluids....such as GM T56's. Try using GL5 MTL's in almost any factory installed Tremec and I think a lot of them will fail or be much harder to shift. If this guy has done thousands of transmissions on GL5 only without a single failure, he probably hasn't done many Tremecs or those specifying 7 cSt ATF's. I can believe that in old Muncies, Saginaws, Chrysler 833's, etc. that GL5 probably is fine. You don't see many trans rebuilders recommending GL5 in ATF specced transmissions....usually they say just the opposite...don't ever use GL5.
 
Maybe this guy hasn't seen GL5 fluids "corrode" synchronizer rings. But the wrong fluid can cause poor synchronization and increase synchro friction ring wear rates. Either way, it leads to shortened synchro life. Some ATF specced manual transmissions can't even take a GL4/GL5 fluid for a single day without constant grinding. I would submit if those were left in the vehicle for weeks and months, a very premature failure would occur.
 
Originally Posted By: zeng



..So, wondering why the fuss on Bitog ?...




What fuss?

There has been a lot of misunderstanding with respect to GL-X protection ratings, the chemistry of MTF dedicated fluids, and Old verses New Technology of these fluids.

When GL-5 rated lubes were the only choice available, then that's what you had to use.

But then we learned about the effects of high treatment level of S-P chemistry on internals, and then GM led the industry in introducing MT dedicated fluids formulated by Texaco.
 
Last edited:
i have found Redline MT-90 to be excellent even in the touchy VAG manuals. my jetta was barely shifting using a new at the time Amsoil lube that was later discontinued, prolly about 2005 but a switch to MT-90 cured it, expensive but worth it IMO!!!
 
Last edited:
Originally Posted By: 69GTX
For the past 20 yrs numerous manual transmissions have been using factory specced ATF, never mind GL4 or GL5 fluids....such as GM T56's. Try using GL5 MTL's in almost any factory installed Tremec and I think a lot of them will fail or be much harder to shift. If this guy has done thousands of transmissions on GL5 only without a single failure, he probably hasn't done many Tremecs or those specifying 7 cSt ATF's. I can believe that in old Muncies, Saginaws, Chrysler 833's, etc. that GL5 probably is fine. You don't see many trans rebuilders recommending GL5 in ATF specced transmissions....usually they say just the opposite...don't ever use GL5.
MUNCIES?
 
Whilst most OEMs recommends GL4 in their manual transmissions, the fact remains there are OEMs (though may be of minority) recommending GL5 in their respective manual transmissions.

GL4 came into market well before GL5 with a gap of at least a decade if I may speculate.GL4 could have 'monopolised' manual transmission lubricants market, but fact remains it's not.

And this GearBoxVideo guy would have seen more GL5 being dumped into more manual transmissions than all of us combined here, let alone personally viewed various worn and trashed conditions of all internal parts of manual transmissions filled up with GL5 prior.

Hence, his comment on haven't seen bronze/brass synchronizers being damaged/corroded by GL5 would be credible, is it not?
 
Originally Posted By: zeng
Whilst most OEMs recommends GL4 in their manual transmissions, the fact remains there are OEMs (though may be of minority) recommending GL5 in their respective manual transmissions.

GL4 came into market well before GL5 with a gap of at least a decade if I may speculate.GL4 could have 'monopolised' manual transmission lubricants market, but fact remains it's not...


The majority of MTF's for cars and light trucks on the market today use the GL-4 protection rated fluids ranging in viscosities from 6.0 to 14.5 cSt@100C.

Manf. specifying GL-5 MTF's is Subaru and a few other manf. in which the differential and transmission share a common sump, and the differential is a hypoid type design. However, this special GL-5 still has friction modifiers for the synchro unit.

Secondly, in terms of volume, the HD and Over-the-Road non-synchronized transmission market uses the GL-5 hypoid-type lube that is also MT1 rated, but this lubricant is formulated much different than the Subaru GL-5 rated "common sump" oil.

When one discusses MTF's, one has to delineate between the various applications.

Otherwise, I still do not see what point you are trying to make.
 
Last edited:
Special cases and applications aside I thought it is a common knowledge that GL-5 fluids predominantly use sulfur based extreme pressure additives that over time corrode brass. Therefore, GL-5 fluids don't go into transmissions with brass synchronizers.

People do say they use GL-5 where GL-4 is specified and no problem. But it is a question of a longer term effect that may not be noticeable in just 1 or 2 years. The question is how such transmission will perform in 50K or 100K miles.
 
Originally Posted By: MolaKule


...Manf. specifying GL-5 MTF's is Subaru and a few other manf. in which the differential and transmission share a common sump, and the differential is a hypoid type design. However, this special GL-5 still has friction modifiers for the synchro unit.

Secondly, in terms of volume, the HD and Over-the-Road non-synchronized transmission market uses the GL-5 hypoid-type lube that is also MT1 rated, but this lubricant is formulated much different than the Subaru GL-5 rated "common sump" oil...



Modern GL-5/MT1 lube formulas use what is known as "buffers" or metal deactivators as well as the fact that S-P chemistry contains a special sulfur chemistry that has little reactivity with copper alloys, which is why they have 1A and 1B ratings.

But here is the big question: Why would anyone use a GL-5 rated hypoid differential lube in a car or light truck MT when there is a wide range of dedicated GL-4 rated MTF's specifically formulated for car and light truck transmissions?
 
Last edited:
Originally Posted By: MolaKule
Modern GL-5/MT1 lube formulas use what is known as "buffers" or metal deactivators as well as the fact that S-P chemistry contains a special sulfur chemistry that has little reactivity with copper alloys, which is why they have 1A and 1B ratings.

But here is the big question: Why would anyone use a GL-5 rated hypoid differential lube in a car or light truck MT when there is a wide range of dedicated GL-4 rated MTF's specifically formulated for car and light truck transmissions?


I expect it's a more-is-better situation - I'm sure many people think that an EP additive designed to prevent wear under extreme pressure will prevent wear better than a garden variety AW additive that isn't good enough handle extreme pressure.
 
Status
Not open for further replies.
Back
Top